Optical path for a thermal-assisted magnetic recording head

ABSTRACT

An optical path or waveguide for a laser-assisted transducing head is disclosed. The optical path extends between the poles of the transducing head to near the write gap. A solid-state laser is attached to or incorporated into the slider or head and is positioned to direct thermal energy through a waveguide and onto a track of a read/write surface to lower the coercivity of the recording medium to facilitate the write process.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation application of U.S. Ser. No.10/600,561, filed Jun. 19, 2003, now U.S. Pat. No. 6,996,033, which is anon-provisional of U.S. Ser. No. 60/389,802 filed Jun. 19, 2002 and60/413,190 filed Sep. 24, 2002; the subject matters of which are herebyincorporated by reference in their entirety.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

This invention was made with United States Government support underAgreement No. 70NANB1H3056 awarded by the U.S. Department of Commerce,National Institute of Standards and Technology (NIST), AdvancedTechnology Program. The United States Government has certain rights inthe invention.

FIELD OF THE INVENTION

This invention relates generally to magnetic recording heads, includinga read element and a write element, for use in a data storage systemsuch as a disk drive. More specifically, it relates to a path for anoptical waveguide to carry thermal energy (e.g., light) to a locationnear the write portion of the magnetic recording head, to enablethermally-assisted writing.

BACKGROUND OF THE INVENTION

Typical disk drive systems include suspensions for supporting atransducing head over information tracks of a rotatable disk. Typically,suspensions include a load beam or suspension having a mounting regionon a proximal end, a flexure or gimbal on a distal end, a relativelyrigid region adjacent to the flexure, and a spring region between themounting region and the rigid region. An air bearing slider which holdsthe transducing head is mounted to the flexure. The mounting region istypically attached to a base plate for mounting the load beam to anactuator arm. A motor which is controlled by a servo control systemrotates the actuator arm to position the transducing head over thedesired information tracks on the disk. This type of suspension may beused with both magnetic and non-magnetic disks.

FIG. 1 shows a top view of a known disk drive actuation system 10, forpositioning a transducing head (not shown) over a track of a magneticdisk. The actuation system 10 includes, as shown from left to right inFIG. 1, a voice coil motor (“VCM”) 12, an actuator arm 14, a load beamor suspension 16, a flexure 18, and a slider 20. The slider 20 isconnected to the distal end of the suspension 16 by the flexure 18. Theload beam 16 is connected to the actuator arm 14 which is coupled to theVCM 12.

As shown on the right-hand side of FIG. 1, the disk drive assemblyincludes a disk 22 having a multiplicity of tracks 24 which rotate aboutan axis 26. During operation of the disk drive assembly, the rotation ofthe disk 22 generates air movement which is encountered by the slider20. This air movement acts to keep the slider 20 aloft a small distanceabove the surface of the disk 22 allowing the slider 20 to “fly” abovethe surface of the disk 22. Any wear associated with physical contactbetween the slider 20 and the disk 22 is thus minimized.

As shown in FIG. 2, the flexure 18 provides a spring connection betweenthe slider 20 and the load beam 16. Flexure 18 is configured such thatit allows the slider 20 to move in pitch and roll directions tocompensate for fluctuations in the spinning surface of the disk 22. Manydifferent types of flexures 18, also known as gimbals, are known toprovide the spring connection allowing for pitch and roll movement ofthe slider 20 and can be used with the present invention.

The VCM 12 is selectively operated to move the actuator arm 14 around anaxis 28 thereby moving the load beam 16 and positioning the transducinghead carried by the slider 20 between tracks 24 of disk 22. Properpositioning of the transducing head is necessary for reading and writingof data on the concentric tracks 24 of the disk 22. For a disk 22 havinga high density, however, the VCM 12 lacks sufficient resolution andfrequency response to position the transducing head on the slider 20over a selected track 24 of the disk 22. Therefore, a higher resolutionmicroactuation system is often used.

The density of concentric data tracks on magnetic disks continues toincrease (i.e., the size of data tracks and radial spacing between datatracks are decreasing). In addition, the linear density continues toincrease, which in turn increases the area bit density in bothdirections and reduced the area per magnetic bet cell. As the area perbit cell is reduced, the number of grains or particles per bit cell isalso reduced unless the grain size is also reduced. The signal-to-noiseratio is a function of the number of grains per bit cell, so as thisdensity increases, it becomes more difficult to write data to the trackswithout affecting adjacent tracks. One technique in the art for enablingprecise data writing is to use thermally-assisted laser writing. Thistechnique requires the presence of a thermal energy source, such as alight beam (e.g., a laser beam) at or near the location of thetransducing head. This thermal energy source provides energy to therecording medium, which reduces the medium's coercivity to facilitatethe write process.

Accordingly, there is a need in the art for an optical path or waveguidefor directing light from a top surface of a slider down to a point nearthe write gap of the magnetic recording head. There is a further needfor a system for directing a laser beam to a position near thetransducing head and onto the recording medium.

BRIEF SUMMARY OF THE INVENTION

The present invention, in one embodiment, is a magnetic recording headfor writing data onto a magnetic recording medium. The head includes afirst pole and a second pole separated by a gap. A coil structuretraverses through the gap, and a waveguide extends through the gap, in aplane distinct from the first pole plane and the second pole plane. Aclosure partially connects the first pole and the second pole near theback gap to decrease a magnetic reluctance and increase a writeefficiency of the recording head.

Another embodiment of the present invention is a load beam assembly fortransducing data with a concentric track of a magnetic recording medium.The assembly includes a slider including an air-bearing surface, and atransducing head mounted on a trailing face of the slider, thetransducing head having a first pole and a second pole. The assemblyfurther includes a light source attached near the trailing face, and awaveguide extending generally straight down from near an upper edge tonear a lower edge of the trailing face, such that the waveguide isdisposed in a distinct plane between the first and second poles.

Yet another embodiment of the present invention is a method offabricating a head/load beam assembly for writing data to a concentrictrack of a magnetic recording medium. The method comprises providing aslider having an air bearing surface, forming a transducing head on atrailing edge of the slider, the transducing head including a polehaving a split back gap, forming a waveguide on the trailing face of theslider, the waveguide extending through the split back gap, and mountinga laser source near the trailing edge of the slider.

While multiple embodiments are disclosed, still other embodiments of thepresent invention will become apparent to those skilled in the art fromthe following detailed description. As will be apparent, the inventionis capable of modifications in various obvious aspects, all withoutdeparting from the spirit and scope of the present invention.Accordingly, the drawings and detailed description are to be regarded asillustrative in nature and not restrictive.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top view of a disk drive actuation system, as known in theprior art.

FIG. 2 is a perspective view of a suspension, flexure, and slider of adisk drive actuation and positioning system, as known in the prior art.

FIG. 3 is a perspective view of a head/gimbal assembly, according to oneembodiment of the present invention.

FIG. 4A is a perspective view of a laser-attached slider, according toone embodiment of the present invention.

FIG. 4B is a perspective view of a laser-attached slider, according to asecond embodiment of the present invention.

FIG. 5A is a perspective view of a transducing head, according to oneembodiment of the present invention.

FIG. 5B is a sectional perspective view and cross-sectional view of aportion of a transducing head, according to one embodiment of thepresent invention.

FIG. 6 is a perspective view of a head/gimbal assembly, according toanother embodiment of the present invention.

FIG. 7A is a sectional view and FIG. 7B is a sectional perspective viewof a slider, according to yet another embodiment of the presentinvention.

DETAILED DESCRIPTION

FIG. 3 is a perspective view of a head/gimbal assembly 100, according toone embodiment of the present invention. As shown in FIG. 3, thehead/gimbal assembly 100 includes a gimbal or flexure 102, a slider 104,and a laser 106. The assembly 100 can be mounted to any load beam knownin the art. The laser 106, in the embodiment shown in FIG. 3, is buttcoupled to the slider 104 in the manner discussed below with referenceto FIG. 4A. As shown, the laser 106 is thermally-coupled to a tab 120,which extends upwardly from the flexure 102.

While the present invention is explained in terms of a laser, otherthermal energy sources can replace the laser and fall within the scopeof the invention. In one embodiment, the laser 106 is a laser diode,such as, for example, the 10 mW laser diode manufactured and sold bySemco Laser Technology of Baldwin Park, Calif. Any other laser diodeknown in the art may also be used in the present invention. In oneembodiment, a laser diode having a power rating of from about 1 to about25 mW is used. In another embodiment, a laser diode having a powerrating of from about 8 to about 15 mW is used. In one embodiment, thelaser provides sufficient power to heat the magnetic media to or aboveits Curie point. The laser diode may have an anode and a cathode forelectrically coupling the laser diode to a power source.

Considerations for selecting and mounting the laser 106 include itspower rating, ease of coupling to a waveguide, effect on slider flyingcharacteristics, and thermal dissipation. The laser 106 should be ableto generate sufficient power to reduce the coercivity of the recordingmedium. The laser 106 should be mounted to the flexure 102 in a mannerthat allows dissipation of heat. In the embodiment of FIG. 3, the laser106 includes two heat transfer surfaces. One full face is in thermalcontact with the tab 120 of the flexure 102 and another face is inthermal contact with the slider 104.

As shown in FIGS. 4A and 4B, a slider 104 includes a disk opposing face110 and a top face 111 bounded by a leading face 112, a trailing face114, and side faces 116 extending from the leading face 112 to thetrailing face 114. The shape and contours of the disk opposing face 110determine the flying characteristics of the slider 104. The slider 104must maintain adequate roll, pitch, and normal stiffness over theconcentric data tracks of the recording medium. FIGS. 4A and 4B furthershow the location of the transducing head 118, which is positioned onthe trailing face 114 near the disk opposing face 110.

FIGS. 4A and 4B show embodiments in which the laser 106 is verticallydisposed on the slider 104. In other words the laser 106 emits lightdirectly into the entrance to the waveguide 126. The laser 106, in theembodiment shown in FIG. 4A is butt coupled to the top face 111 andsecured with any known technique, including by use of an adhesive. Asshown, the laser 106 is configured such that the light-emitting centerportion of the laser 106 is aligned with the waveguide 126. Any knownactive alignment technique can be used to optimize alignment of thelaser 106 with the waveguide 126. The top portion or entrance of thewaveguide 126 includes an optical grading, which directs the light intothe waveguide 126. In another embodiment, the laser 106 is free spacecoupled to the waveguide 126. In other words the laser 106 is mountedabove the entrance of the waveguide 126 located on the slider 104.

In the embodiment of FIG. 4B, the laser 106 is mounted to the trailingface 114, which places one full face of the laser 106 in contact withthe slider 104. In the embodiment shown, the laser 106 is set into apocket formed in the trailing face 114 by a known technique such as ionmilling. This configuration can provide additional stability and assistwith proper alignment of the laser 106 with the waveguide 126. Again,active alignment can be used to optimize alignment of the laser 106 withthe waveguide 126.

The waveguide 126 may be fabricated from any material known in the artcapable of transmitting or conducting the laser beam from the lasersource to a position near the write portion of the transducing head. Thewaveguide 126 is sized and shaped in any manner known in the art toconduct the laser beam effectively. The waveguide 126 may be constructedfrom one material or from multiple materials. The waveguide 126 caninclude one or more condensing or transducing elements to assist indirecting the light to the write gap to effectively heat the magneticmedia.

FIGS. 5A and 5B show a perspective view and a sectional perspective viewof a portion of the transducing head 118, according to one embodiment ofthe present invention. The transducing head 118 is formed near the loweredge of the trailing face of the slider 104. As shown in FIGS. 5A and5B, the transducing head 118 includes a first pole 130, a second pole132, and a read/write coil 134. An optical path or waveguide 126 extendsfrom at or near the top face of the slider 104 to near the write gap 40.As shown, the waveguide 126, in this embodiment, extends along a frontface of the first pole 130. The read/write coil 134 extends along afront face of the first pole 130 and behind the second pole 132. Theread/write coil 134 travels between the waveguide 126 and the secondpole 132. The read/write coil 134 is insulated from the poles 130, 132by an insulating layer.

As further shown in FIG. 5A, the second pole 132 includes a twin, orsplit, back gap through which the waveguide 126 travels. Thisconfiguration allows the waveguide 126 to extend to a point near thewrite gap 40 of the transducing head 118, without requiring any bendingor turning of the waveguide 126. As shown in FIG. 5A, the second pole132 includes a first closure 44 and a second closure 46. The closures44, 46 act to strengthen the magnetic circuit conducted by the firstpole 130 and the second pole 132, which reduces the magnetic reluctanceand the power that must be supplied by the coil 134. This, in turn,increases the write efficiency of the head. Various other closed backgap configurations can also be used, which allow the waveguide 126 totravel to the distal end of the transducing head 118, without bending orturning. In one embodiment of the present invention, the closures 44, 46are not present. In this open back gap configuration, the opposing poleareas must be sufficiently large to reduce the magnetic reluctancerelative to the write gap 40. For example, in one embodiment theopposing area of the back gap is from about 10 to about 100 times largerthan the opposing area of the write gap 40.

As shown in FIGS. 5A and 5B, the waveguide 126 terminates at atermination point 48 near a distal end of the transducing head 118. Anoptical condenser or transducer (not shown) is typically coupled to thetermination point 48 of the waveguide 126 to direct the light into thewrite gap 40. According to another embodiment of the present invention,the waveguide 126 travels between the coil 134 and the second pole 132.

FIGS. 6, 7A, and 7B show various head/gimbal or load beam assemblies formounting or coupling a laser source to the disclosed waveguide. FIG. 6is a perspective view of a head/gimbal assembly 130, according toanother embodiment of the present invention. As shown in FIG. 6, thehead/gimbal assembly 130 includes a gimbal or flexure 132, a slider 134,and a laser source 136. The assembly 130 can be mounted to any load beamknown in the art. As shown in FIG. 6, the assembly 130 further includesone or more tabs 138 projecting upward from the flexure 132. The tabs138 may be integrally formed from the flexure 132 or may be coupled tothe flexure 132. The embodiment shown in FIG. 6 includes four heattransfer surfaces to accomplish cooling of the laser source 136. In theembodiment of FIG. 6, the beam from the laser source 136 is turnedninety-degrees, using any known technique, to direct the beam in adirection generally perpendicular to the major plane of the slider 134.For example, a forty-five degree mirror 139 could be positioned betweenthe output of the laser and the input of the waveguide.

FIG. 7A is a sectional view and FIG. 7B is a perspective view of aslider 140, according to yet another embodiment of the presentinvention. In this embodiment, the laser source (not shown) is locatedsomewhere upstream (i.e., off board) from the slider 140 and the lightfrom the laser source is carried to the slider 140 by an optical fiber146. The assembly 140 can be mounted to a head/gimbal assembly, whichcan in turn be mounted to any load beam known in the art. The opticalfiber 146 can be any fiber, as known in the art, capable of conductingthe laser beam from the laser source to a location near the trailingedge of the slider 140. For example, the optical fiber 146, in oneembodiment, is 80 micron RC SMF 28 Corning fiber or any othersingle-mode multi-mode fiber commercially available, including plasticoptical fiber. In one embodiment, the optical fiber 146 could be coveredwith a protective coating or buffer.

As shown in FIGS. 7A and 7B, the slider 140 includes a slider base 148and a top 150. A focusing ball 152 is located adjacent a distal end ofthe optical fiber 146 and focuses light exiting the optical fiber 146toward a forty-five degree coupling surface or mirror 154. The couplingmirror 154 directs the light beam 156 into the entrance to the waveguide126. Again, the entrance to the waveguide 126 includes an opticalgrading that collects light and focuses it along the waveguide 126. Thisstructure is also commonly referred to as a silicon optical bench.

Although the present invention has been described with reference topreferred embodiments, persons skilled in the art will recognize thatchanges may be made in form and detail without departing from the spiritand scope of the invention.

1. A head/load beam assembly for transducing data with a concentrictrack of a magnetic recording medium, the assembly comprising: a sliderincluding an air-bearing surface; a transducing head mounted on atrailing face of the slider, the transducing head having a first poleand a second pole separated by a gap; a closure partially connecting thefirst pole and the second pole generally at the back of the first poleand the second pole, the closure including a first closure and a secondclosure split apart from each other; and a waveguide disposed in adistinct plane between the first and second poles and extending withinthe gap and between the first and second closures without bending,turning, or extending within the first pole or the second pole so as todecrease a magnetic reluctance and increase a write efficiency of thetransducing head.
 2. The assembly of claim 1 wherein a light source isattached near the trailing face.
 3. The assembly of claim 2 wherein thelight source includes a light emitting face, and wherein the lightemitting face is disposed generally opposing an upper face of theslider.
 4. The assembly of claim 2 wherein a power output of the lightsource is sufficient to cause heating of a portion of the magneticrecording medium located near a write gap to a Curie temperature of themagnetic recording medium.
 5. The assembly of claim 2 further includinga flexure adapted for supporting the slider and the light source.
 6. Theassembly of claim 1 wherein the transducing head further includes atransducing coil, the transducing coil extending between the first andthe second poles.
 7. The assembly of claim 1 wherein a light source isattached to the trailing face, such that a face of the light source isin contact with the trailing face.
 8. A process of writing data onto amagnetic recording medium comprising: writing data onto the magneticrecording medium using a magnetic recording head comprising: a firstpole and a second pole separated by a gap; a coil structure traversingthrough the gap; a waveguide extending through and within the gap, in aplane distinct from the first pole and the second pole; and a closurepartially connecting the first pole and the second pole disposedproximate a back of the first pole and the second pole, the closureincluding a first closure and a second closure split apart from eachother; wherein the waveguide extends between the first and secondclosures without bending, turning, or extending within the first pole orthe second pole so as to decrease a magnetic reluctance and increase awrite efficiency of the recording head; directing thermal energy throughthe waveguide to provide thermally-assisted writing.
 9. The process ofwriting data onto a magnetic recording medium of claim 8, wherein thewaveguide travels through a split gap between the first closure and thesecond closure such that the thermal energy can travel in a straightpath from an entrance of the waveguide to a write gap area of the head.10. The process of writing data onto a magnetic recording medium ofclaim 9, wherein the thermal energy is transduced onto the magneticrecording medium.
 11. The process of writing data onto a magneticrecording medium of claim 8, wherein the waveguide is disposed betweenthe first pole and the coil structure.
 12. A process of writing dataonto a magnetic recording medium comprising: providing a load beamassembly comprising: a slider including an air-bearing surface; atransducing head mounted on a trailing face of the slider, thetransducing head having a first pole and a second pole separated by agap; a closure partially connecting the first pole and the second polegenerally at the back of the first pole and the second pole the closureincluding a first closure and a second closure split apart from eachother; and a waveguide disposed in a distinct plane between the firstand second poles and extending within the gap and between the first andsecond closures without bending, turning, or extending within the firstpole or the second pole so as to decrease a magnetic reluctance andincrease a write efficiency of the transducing head; writing data ontothe magnetic recording medium using the transducing head; and directingthermal energy through the waveguide to provide thermally-assistedwriting.
 13. The process of writing data onto a magnetic recordingmedium of claim 12, wherein a light source is attached near the trailingface.
 14. The process of writing data onto a magnetic recording mediumof claim 13, wherein the light source includes a light emitting face,and wherein the light emitting face is disposed generally opposing anupper face of the slider.
 15. The process of writing data onto amagnetic recording medium of claim 13, wherein a power output of thelight source is sufficient to cause heating of a portion of the magneticrecording medium located near a write gap to a Curie temperature of themagnetic recording medium.
 16. The process of writing data onto amagnetic recording medium of claim 13, further including a flexureadapted for supporting the slider and the light source.
 17. The processof writing data onto a magnetic recording medium of claim 12, wherein alight source is attached to the trailing face, such that a face of thelight source is in contact with the trailing face.
 18. The process ofwriting data onto a magnetic recording medium of claim 12, wherein thetransducing head further includes a transducing coil, the transducingcoil extending between the first and the second poles.